The Adolescent Component of the National Comorbidity Study (NCS-A) is a combined probability and school-based multi-ethnic sample of 10,000 US adolescents. Dr. David Offord and his team at McMaster University and our research group at Yale adapted the adult diagnostic interview for adolescents. This study provides the first national data on the prevalence and correlates of mental disorder in youth in the general population. Our research team has worked collaboratively with other national experts to select a series of measures of risk factors for major mental disorders. [unreadable] [unreadable] Our research group devoted substantial effort to the design and implementation of the study and the analyses. During the past year, our efforts have been devoted to data cleaning, defining secondary variables, preparing the papers describing the study design, methods and measures, and conducting analyses for the initial publications of the adolescent data. [unreadable] [unreadable] Our analyses of the clinical reappraisal study yielded good aggregate consistency between CIDI and K-SADS prevalence estimates, although CIDI prevalence estimates were generally somewhat higher than K-SADS estimates. Strong individual-level concordance of CIDI and K-SADS diagnoses was found for most diagnoses, with an inter-quartile range (25th-75th percentiles) of the area under the ROC (Receiver Operating Curve) curve (AUC, a measure of classification accuracy that is not influenced by disorder prevalence) of .84-.92. AUC was .88 for any anxiety disorder, .89 for any mood disorder, .84 for any externalizing disorder, .94 for any substance disorder, and .87 for any disorder. Although AUC was unacceptably low for a small number of disorders, most notably alcohol dependence and bipolar I and II disorders, these problems were resolved by aggregation (i.e., combining alcohol abuse with dependence and bipolar I with bipolar II disorders). Logistic regression analysis documented that consideration of CIDI symptom-level data significantly improved prediction of some K-SADS diagnoses. [unreadable] [unreadable] During the next year, we plan to conduct analyses of the prevalence and correlates of mood and anxiety disorders, to examine patterns of comorbidity between mental and physical disorders in children and to complete the stress hormone assays and evaluate their association with mental disorders in children.